Øivind Hodnebrog, Gunnar Myhre, Caroline Jouan
et al.
Abstract The Earth’s energy imbalance is the net radiative flux at the top-of-atmosphere. Climate model simulations suggest that the observed positive imbalance trend in the previous two decades is inconsistent with internal variability alone and caused by anthropogenic forcing and the resulting climate system response. Here, we investigate anthropogenic contributions to the imbalance trend using climate models forced with observed sea-surface temperatures. We find that the effective radiative forcing due to anthropogenic aerosol emission reductions has led to a 0.2 ± 0.1 W m−2 decade−1 strengthening of the 2001–2019 imbalance trend. The multi-model ensemble reproduces the observed imbalance trend of 0.47 ± 0.17 W m−2 decade−1 but with 10-40% underestimation. With most future scenarios showing further rapid reductions of aerosol emissions due to air quality legislation, such emission reductions may continue to strengthen Earth’s energy imbalance, on top of the greenhouse gas contribution. Consequently, we may expect an accelerated surface temperature warming in this decade.
Soil organic carbon (SOC) is central to the functioning of terrestrial ecosystems, has climate mitigation potential and provides several benefits for soil health. Understanding the spatial distribution of SOC can help formulate sustainable soil management practices. Digital soil mapping (DSM) uses advanced statistical and geostatistical methods to estimate soil properties across large areas. DSM integrates climate data, topographic features, geology, legacy soil maps, land management and remote sensing data. Bare soil spectra may reflect the presence of particular soil components, making satellite derived spectra suitable predictors of SOC. Bare soil spectra derived from Sentinel-2 were used to estimate SOC concentration (SOC%) and granulometric fractions in the plough layer (0–30 cm) of agricultural parcels in northern Belgium. Thereafter, the estimation performance of SOC% was compared for three DSM models: one with bare soil spectra, one with environmental covariates (topography, granulometry and vegetation), and a combined model with bare soil spectra and environmental covariates. The estimation performance of sand, silt and clay fractions using bare soil spectra from the spring seedbed (R2: 0.53–0.74; RPD: 1.49–2.05; RPIQ: 1.52–2.39) was higher than that of SOC% (R2: 0.16; RPD: 1.08; RPIQ: 1.32). The highest estimation performance of SOC% was obtained for a DSM model including all covariates (R2: 0.28; RPD: 1.18; RPIQ: 1.44), but the contribution of spring seedbed spectra to a model containing environmental covariates was small. The results provide valuable insights for refining soil property estimation using DSM with spectral and environmental covariates.
Stanisław Burliga, Marek Kasprzak, Artur Sobczyk
et al.
Long-term draining of peatlands results in transformation of vegetation and obliteration of their morphological features. In many areas, efforts are made to restore the original ecosystems and increase their water retention potential. Using combined analyses of a LiDAR-based digital terrain model (DTM), colour-infrared (CIR) imagery data, ground-penetrating radar (GPR) data and electrical resistivity tomography (ERT) data, we tested the applicability of these methods in outlining the extent and subsurface structure of drained mires located in the Stolowe Mountains National Park area, Poland. The LiDAR-DTMs enabled parameterisation of physiographic features of the mires and determination of their extent, runoff directions and potential waterlogging areas. CIR analysis enabled classification of vegetation types. GPR prospecting revealed the bedrock morphology, thickness and internal structure of the peat deposits, showing that this technique can also provide data on variability in the decomposition of phytogenic deposits. The obtained ERT sections indicate both the thickness of peat deposits and variability in the bedrock internal structure. The results show that integrated analyses of data obtained with different methods can be an effective tool in outlining the original extent of peatlands, with potential application in the planning of peatland ecosystem restitution.
Igor Medved, Nediljka Gaurina-Međimurec, Karolina Novak Mavar
et al.
Drilling fluid represents the most important fluid that must fulfill numerous important assignments during drilling operations. Many commercially available additives for water-based drilling fluid fall into the category of non-degradable and environmentally hazardous materials. Significant development in this area can be made by using biodegradable materials as additives in drilling fluids. The objective of this study was to determine whether mandarin peel powder particle size affects the properties of the drilling fluid. In this paper, mandarin peel was used in the form of a dry powder divided into particle sizes smaller than 0.1 mm, and between 0.1 mm and 0.16 mm. Mandarin peel powder was added to a water-based drilling fluid in four different concentrations (0.5, 1, 1.5, and 2% by volume of water). By increasing the mandarin peel powder concentration, the API filtration reduced up to 42%, PPT filtration significantly decreased up to 61.54%, while the rheological parameters generally increased but remained within acceptable limits. It is determined that the optimal concentration of mandarin peel powder is up to 1.5% by volume of water.
<p>The management of agricultural soils during crop establishment can affect
root development due to changes in the soil structure. This paper assesses the
influence of tillage depth (250 mm, 100 mm, and zero tillage) and traffic management
(conventional tyre pressure, low tyre pressure, and no traffic) on wheat
root system architecture during winter wheat (<i>Triticum aestivum</i> L.) tillering and flowering
growth stages (GS) at a long-term tillage trial site. The study revealed
that zero-tillage systems increased crop yield through significantly greater
root biomass (<span class="inline-formula"><i>P</i><i><</i>0.001</span>), root length density, and deeper seminal
rooting analysed using X-ray computed tomography (CT) (<span class="inline-formula"><i>P</i><i><</i>0.001</span>)
compared with trafficked treatments. In general, conventional-pressure
traffic had a significant negative influence on the crop yield (<span class="inline-formula"><i>P</i><i><</i>0.01</span>), root development (0.001), bulk density (<span class="inline-formula"><i>P</i><i><</i>0.05</span>), and total
soil porosity (<span class="inline-formula"><i>P</i><i><</i>0.05</span>) of deep- and shallow-tillage conventional-pressure systems compared with no-traffic zero- and deep-tillage systems. Visual
improvements in soil structure under zero-tillage conditions may have improved crop
rooting in zero-tillage treatments through vertical pore fissures
(biopores), enhancing water uptake during the crop flowering period. This
study highlights the increasing implications of soil structural damage on
root system architecture created by machinery traffic in crop
production. Although the tillage method was less important, the constricted root
systems were more pronounced in conventional-pressure shallow-tillage and
deep-tillage systems, emphasizing the importance of using controlled-traffic
farming methods to improve soil management and reduce the trafficked areas
of agricultural fields.</p>
Abstract The Colorado Plateau and its surroundings serve as an archetypal case to investigate the interaction of mantle melting processes and lithospheric structure. It has been hypothesized that widespread Cenozoic volcanism indicates the encroachment of the convective upwelling of asthenosphere toward the Plateau center. In this study, we generate a Common Conversion Point (CCP) stack of S‐to‐p (Sp) receiver functions to image the locations of lithospheric discontinuities in the southwestern United States. Our results are broadly similar to prior work, showing a strong and continuous Negative Velocity Gradient (NVG) consistent with the Lithosphere‐Asthenosphere Boundary (LAB) over much of the study area. However, with several methodological improvements, we are able to obtain more reliable NVG depth picks below the Colorado Plateau where the LAB becomes weaker, deeper, and broader. We compare the inferred topography of NVGs with the locations of volcanoes, and find that the majority of recent volcanoes are co‐located with lithosphere that is ∼80 km thick. This appears to be the critical depth at which partial melt from upwelling asthenosphere pooling at the base of (or within) the lithosphere may percolate to the surface. We compare our CCP profiles with magma equilibration conditions determined from petrologic analysis and find good agreement between the depth of NVGs and depth of magma equilibration. This analysis provides insight into the progression of magmatism and lithospheric loss toward the center of the Colorado Plateau, and demonstrates how small‐scale processes like melting influence lithosphere‐asthenosphere interactions that persist over large temporal and spatial scales.
To examine the spatial pattern and controlling factors of the primary productivity (PP) of phytoplankton in the eastern Indian Ocean (EIO), deck-incubation carbon fixation (a 14C tracer technique) and the related hydrographic properties were measured at 15 locations during the pre-summer monsoon season (February–April 2017). There are knowledge gaps in the field observations of PP in the EIO. The estimated daily carbon production rates integrated over the photic zone ranged from 113 to 817 mgC m–2 d–1, with a mean of 522 mgC m–2 d–1. The mixed-layer integrated primary production (MLD-PP) ranged from 29.0 to 303.7 mgC m–2 d–1 (mean: 177.2 mgC m–2 d–1). The contribution of MLD-PP to the photic zone-integrated PP (PZI-PP) varied between 19 and 51% (mean: 36%). Strong spatial variability in the carbon fixation rates was found in the study region. Specifically, the surface primary production rates were relatively higher in the Bay of Bengal domain affected by riverine flux and lower in the equatorial domain owing to the presence of intermonsoonal Wyrtki jets, which were characterized by a depression of thermocline and nitracline. The PZI-PP exhibited a linear (positive) relationship with nutrient values, but with no significance, indicating a partial control of macronutrients and a light limitation of carbon fixation. As evident from the vertical profiles, the primary production process mainly occurred above the nitracline depth and at high photosynthetic efficiency. Phytoplankton (>5 μm), including dinoflagellates, Trichodesmium, coccolithophores, and dissolved nutrients, are thought to have been correlated with primary production during the study period. The measured on-deck biological data of our study allow for a general understanding of the trends in PP in the survey area of the EIO and can be incorporated into global primary production models.
Science, General. Including nature conservation, geographical distribution
Se realizaron dos muestreos en marea baja, uno en diciembre (2009) y el otro en enero (2010) para determinar los microorganismos existentes en el Estero Salado que son los indicadores de contaminación. Un total de nueve estaciones
fueron ubicadas a lo largo del Estero Salado en los Tramos B, D, E y G. Los resultados obtenidos en diciembre del 2009 indican una fuerte contaminación bacteriana en el agua, cuyos valores variaron desde 180NMP/100 mL hasta 160000NMP/100 mL en coliformes totales, coliformes fecales y escherichia coli, en cambio los valores para enterococos fueron de 180NMP/100 mL hasta 7900 NMP/100 mL; para los sedimentos los valores fueron desde 360NMP/100 g hasta 110000 NMP/100g para coliformes totales, coliformes fecales y E. coli y para los enterococos, los valores fueron 300NMP/g hasta 29000NMP/g, estos resultados están por encima de los niveles máximos permitidos. Dentro de los parámetros físicos químicos que afectan a la contaminación fueron la alinidad,
el oxigeno disuelto y la temperatura. En enero (2010), los coliformes totales en el agua tuvieron valores entre 84 NMP/100 mL y 7000 NMP/100mL, para los coliformes fecales (4NMP/100mL – 450NMP/100mL), E. coli (1,8 NMP/100mL -180 NMP/100mL) y los enterococos (6NMP/100mL- 610NMP/100mL). En sedimento, los valores fueron relativamente bajos en comparación con los datos de sedimentos en diciembre. Los datos obtenidos indican que existen variaciones muy marcadas en las estaciones dentro del Estero Salado, lo cual se presume que existe un proceso continuo de contaminación.
José Alberto Pons-Herrera, María Caridad Ramírez-Pérez, Rafael Quintana-Puchol
et al.
The purpose of this study is to determine the phase transformation and thermal performance of the serpentinized dunites of Moa-Baracoa region subjected to temperatures between 1 200 ° C and 1 600 ° C. To fulfill this purpose X-ray diffraction analysis and thermal analysis (gravimetric and differential) were carried out. Heating the dunites at such temperatures produced a stabilization of the forsterite and periclase phases, which gives important refractory properties to this material which support using this raw material in the metallurgical foundry processes.
The purpose of this study was to provide training curriculum model in improving community-based geological hazard mitigation competency. The goal was achieved through research and development method, is divided into three main stages. First, applied need analysis as the introduction. Second, developed the curriculum model. Third, tested the curriculum model in order to explore the curriculum effectiveness in improving the competency for mitigation measurement related to geological hazard. This study showed that the training curriculum model, which is developed based on the result of need analysis, is effective to improve the participant’s competency. The result of pre-post test shows that the improvement of the participant’s cognitive aspect. The significant improvement is identified in the training competency showing the effectiveness of Test II in improving the participant’s practical competency to carry out the training. Some factors that support the training curriculum model development related to community-based Landslides management are: (a) the public servant’s competency for geological hazard mitigation; (b) the motivation of the community who becomes the volunteer; and (c) support from the decision maker. On the other hand, the inhibitors are the lack of competency for training related to geological field, the lack of educational background and knowledge of geology and landslides, and the lack of time.
Soil seed banks are important to the maintenance and restoration of floras. Extant seed banks
exhibit unique characteristics with regard to the distribution of seed size and seed density. Seeds were recovered
from the Upper Pennsylvanian Wise Formation in southwest Virginia. Structurally preserved seeds were also
examined from coal balls of the Pennsylvanian Pottsville and Allegheny Groups, Ohio. The size distribution of
the seeds from the Wise Formation is similar to that of structurally preserved seeds of the Upper Pennsylvanian
Pottsville and Allegheny Group coal balls. In contrast, the seed size distributions in extant wetland, grassland,
woodland and forest habitats are significantly narrower than that of seeds from the Pennsylvanian seed banks.
Larger seeds are less dependent on light for germination, and aid in seedling establishment more than smaller
seeds, especially in dense stable forests where disturbance events are rare. Large seed size may contribute to
increased seed longevity, which reduces the effect of environmental variability on seed germination and development.
The significantly larger size of the Palaeozoic seeds may have imparted an advantage for seedling establishment
in the dense Palaeozoic forests. The preponderance of large seeds may be a result of the absence of large
seed predators (e.g. herbivorous tetrapods), and may have been an evolutionary strategy to minimize damage to
the embryo from a predator population dominated by small invertebrates with chewing or sucking mouthparts.
The estimated seed density of 192 seeds/m2 in the Palaeozoic seed bank falls within the range of modern seed
banks, but at the lower end of modern seed bank densities in a variety of habitats.
The particulate discrete element method (DEM) can be employed to capture the response of rock, provided that appropriate bonding models are used to cement the particles to each other. Simulations of laboratory tests are important to establish the extent to which those models can capture realistic rock behaviors. Hitherto the focus in such comparison studies has either been on homogeneous specimens or use of two-dimensional (2D) models. In situ rock formations are often heterogeneous, thus exploring the ability of this type of models to capture heterogeneous material behavior is important to facilitate their use in design analysis. In situ stress states are basically three-dimensional (3D), and therefore it is important to develop 3D models for this purpose. This paper revisits an earlier experimental study on heterogeneous specimens, of which the relative proportions of weaker material (siltstone) and stronger, harder material (sandstone) were varied in a controlled manner. Using a 3D DEM model with the parallel bond model, virtual heterogeneous specimens were created. The overall responses in terms of variations in strength and stiffness with different percentages of weaker material (siltstone) were shown to agree with the experimental observations. There was also a good qualitative agreement in the failure patterns observed in the experiments and the simulations, suggesting that the DEM data enabled analysis of the initiation of localizations and micro fractures in the specimens.
Engineering geology. Rock mechanics. Soil mechanics. Underground construction
Available data on Early Cretaceous Antarctic ferns, based on mega and microfossils from Cerro Negro Formation (Shetland Islands) in Livingston Island are evaluated, together with the information provided by recently collected fossils. Anatomically well preserved Osmundaceous stems are common in the fossil assemblage. The cyatheaceae are represented by fertile foliage with spores in situ and the first Antarctic petrified stems of this family are found in Cretaceous strata. Fertile structures support the presence of Marattiaceae in the flora. Spores of Lophosoriaceae and other families are present. This diversity suggests that ferns successfully inhabited these Antarctic areas during the Early Cretaceous, therefore at least warm, frost-free paleoclimatic conditions are proposed.
KEY WORDS. Cretaceous. Antarctica. Cerro Negro Formation. Ferns.
This article is a review of the foundation (in 1838) and later developments
of the Helsinki (Finland) magnetic and meteorological observatory, today the
Finnish Meteorological Institute (FMI). The main focus of the study is in
the early history of the FMI up to the beginning of the 20th century.
<br><br>
The first director of the observatory was Physics Professor Johan Jakob
Nervander (1805–1848). He was a famous person of the Finnish scientific,
academic and cultural community in the early decades of the 19th century.
<br><br>
Finland was an autonomously part of the Russian Empire from 1809 to 1917,
but the observatory remained organizationally under the University of
Helsinki, independent of Russian scientific institutions, and funded by the
Finnish Government. Throughout the late-19th century the Meteorological
Institute was responsible of nationwide meteorological, hydrological and
marine observations and research. The observatory was transferred to the
Finnish Society of Sciences and Letters under the name the Central Meteorological Institute
in 1881. The focus of the work carried out in the Institute was changed
gradually towards meteorology. Magnetic measurements were still continued
but in a lower level of importance.
<br><br>
The culmination of Finnish geophysical achievements in the 19th century was
the participation to the International Polar Year programme in 1882–1883 by
setting up a full-scale meteorological and magnetic observatory in
Sodankylä, Lapland.